Finely grate 1 tsp. zest from the lemon and then juice the lemon.
Heat the oil in a 12-inch skillet over medium heat until shimmering hot. Add the onion and garlic and cook, stirring frequently, until the onion begins to soften, 3 to 5 minutes. Add the chicken, lemon zest, cumin, 1/2 tsp. salt, a...